Fungal diseases are common problems in crop agriculture. Many strides have been made against plant diseases as exemplified by the use of hybrid plants, pesticides and unproved agricultural practices. However, as any grower or home gardener can attest, the problems of fungal plant disease continue to cause difficulties in plant cultivation. Thus, there is a continuing need for new methods and materials for solving the problems caused by fungal diseases of plants. These problems can be met through a variety of approaches. For example, the infectious organisms can be controlled through the use of agents that are selectively biocidal for the pathogens. Another method is interference with the mechanism by which the pathogen invades the host crop plant. Yet another method, in the case of pathogens that cause crop losses, is interference with the mechanism by which the pathogen causes injury to the host crop plant. Still another method, in the case of pathogens that produce toxins that are undesirable to mammals or other animals that feed on the crop plants, is interference with toxin production, storage, or activity.
Within the Fusarium sp. are several important pathogens of corn and other cereals in various countries. In corn, Fusarium is known to cause root, stem and ear rot that results in severe crop reduction. The etiology of Fusarium ear mold is poorly understood, although physical damage to the ear and certain environmental conditions can contribute to its occurrence (Nelson PE (1992) "Taxonomy and Biology of Fusarium moniliforme." Mycopathologia 117: 29-36). Fusarium may be isolated from most field grown maize, when no visible mold is present. The relationship between seedling infection and the stalk and ear diseases caused by Fusarium is not clear. Genetic resistance to visible kernel mold has been identified.(Gendloff E, Rossman E, Casale W, Isleib T, Hart P, 1986, "Components of resistance to Fusarium ear rot in field corn." Phytopathology 76: 684-688; Holley RN, Hamilton PB, Goodman MM, 1989, "Evaluation of tropical maize germplasm for resistance to kernel colonization by Fusarium moniliforme." Plant Dis 73: 578-580). The mycotoxins produced by the Fusarium species that infect plants may accumulate in infected plants or in stored grains, presenting serious health consequences for livestock, humans, and other consumers of meat or other food products of such livestock. Fusarium infection has been associated with chronic or acute mycotoxicoses in both farm animals and man (Botallico, et al.). An important mycotoxin that has been found to be produced by certain Fusarium sp. and has been identified in Fusarium infected crops is beauvericin.
Beauvericin is a fungal toxin produced by various Fusarium species, as well as the fungus Beauveria bassiana. Beauvericin is a cyclic peptide, with toxic effects on insects as well as both human and murine cell lines. The activity of beauvericin is due to the ionophoric properties of the compound. Beauvericin is capable of forming complexes with alkali metal cations and affects ion transport across cell membranes. In addition, beauvericin has been reported to be one of the most powerful inhibitors of cholesterol acetyltransferase. Beauvericin has also been shown to induce a type of cell death very similar to apoptosis. Circumstantial evidence further indicates that beauvericin acts in concert with other Fusarium toxins to cause additional toxic effects (1).
Beauvericin has been reported to be found at significant levels in corn from Italy, Peru, and Poland (1,2,3). It is likely that beauvericin will also be found in other areas as more studies are completed. Fusarium species are found in virtually all moldy as well as healthy corn. Food safety is an important issue for grain growers. The European Commonwealth is considering imposing limits on various mycotoxin levels of imported grain.
There is a need in the art for novel methods with which beauvericin may be eliminated from a plant or harvested grain. It is considered important by those skilled in the art to continue to develop inventions in order to protect the final consumer of a plant or harvested grain. The present invention provides the reagents and methodologies necessary to ameliorate plants and harvested grains from beauvericin.